Using a device stolen from time-travelling researchers, Steve and Dan return to the day of the Spindrift's launch and try to alter history and stop the ill-fated flight.

Steve is turned into a raving paranoid by exposure to mushroom spores, and cuts a deal with Inspector Kobick to betray his crewmates.

An alien piper, claiming to be the Pied Piper of Hamlin, brings his act to the Land of the Giants.

A friendly Giant has a teleport device that can send the Spindrift crew back to Earth, but the SID use the whole thing as a trap.

Valerie is forced to act as a toy ballerina in a giant's scheme to kill his rich uncle.

When Chipper is injured by a giant dog, Barry and the others must turn to a giant veterinarian and his sadistic son for assistance.

A giant scientist performs cloning experiments on the Earthlings.

Fitzhugh and Steve accidentally return to Earth in a space-time pod but end up in 1900 and must deal with hostile villagers.

The Earthlings become involved in the politics of a secret underground city.

The Earthlings aid a giant trumpet player against crooks.

The Earthlings become involved in a scientist's scheme to build an indestructible android.

The Earthlings must play a game of real-life chess with a demented giant industrialist.

The Earthlings become involved in a sabotage scheme to destroy the nearby city.

The Earthlings come to the aid of a convicted criminal who has been falsely accused.

Two time travellers from 5477 come to the Land of the Giants to conquer Earth.

A sadistic child unleashes his mechanical toys on the hapless Earthlings.

While working with a helpful Giant scientist, the Earthlings are subjected to radiation which causes strange hallucinations.

Mark is framed for the murder of two Giants and begins acting suspiciously, turning his crewmates against him.

The Earthlings aid an injured puppeteer by pretending to be his dancing puppets, but the owner soon suspects they are involved and prepares to capture them for the reward.

The Spindrift come to the aid of a has-been horror actor but during his comeback movie they find themselves in danger from his enthusiastic director.

Fitzhugh is captured by the owner of a wax museum who is involved in a stolen-diamond racket.

Barry and Valerie are carried off in a balloon to a distant land ruled by a malevolent dictator.

The Earthlings become involved with a superstitious Irish Giant who believes they're leprechauns.

The Earthlings become involved with twin brothers who are plotting to take over the planet.

Fitzhugh tries to use his gambling expertise to pick the winners at a local racetrack, but has to enter into a deal with a giant to do so.